The research program is designed to elucidate the role of chromosomal proteins in the regulation of gene transcription during mammalian spermatogenesis. This will be accomplished by utilizing isolated populations of primitive type A spermatogonia, type A spermatogonia, type B spermatogonia, preleptotene primary spermatocytes, leptotene and zygotene primary spermatocytes, pachytene primary spermatocytes, round spermatids, residual bodies and mature spermatozoa. An in depth ultrastructural characterization of the isolated cells will be undertaken initially to assess whether the cells have retained normal morphology. This will be followed by studies on the characterization of chromosomal proteins using both linear and two-dimensional SDS-polyacrylamide gel electrophoresis. The synthesis of chromosomal proteins at discrete stages of spermatogenesis will be examined by fluorography of two dimensional polyacrylamide gels. The synthesis of specific chromosomal proteins will be correlated with alterations in chromatin structure and changes in the pattern and rate of RNA synthesis.